eth, eth/fetcher: cache future propagated blocks too

eth/fetcher/fetcher.go

@@ -56,6 +56,7 @@ type inject struct {
 type Fetcher struct {
 	// Various event channels
 	notify chan *announce
+	insert chan *inject
 	filter chan chan []*types.Block
 	quit   chan struct{}
 
@@ -69,6 +70,7 @@ type Fetcher struct {
 func New(hasBlock hashCheckFn, importBlock blockImporterFn, chainHeight chainHeightFn) *Fetcher {
 	return &Fetcher{
 		notify:      make(chan *announce),
+		insert:      make(chan *inject),
 		filter:      make(chan chan []*types.Block),
 		quit:        make(chan struct{}),
 		hasBlock:    hasBlock,
@@ -106,6 +108,20 @@ func (f *Fetcher) Notify(peer string, hash common.Hash, time time.Time, fetcher
 	}
 }
 
+// Enqueue tries to fill gaps the the fetcher's future import queue.
+func (f *Fetcher) Enqueue(peer string, block *types.Block) error {
+	op := &inject{
+		origin: peer,
+		block:  block,
+	}
+	select {
+	case f.insert <- op:
+		return nil
+	case <-f.quit:
+		return errTerminated
+	}
+}
+
 // Filter extracts all the blocks that were explicitly requested by the fetcher,
 // returning those that should be handled differently.
 func (f *Fetcher) Filter(blocks types.Blocks) types.Blocks {
@@ -192,6 +208,11 @@ func (f *Fetcher) loop() {
 			}
 			announced[notification.hash] = append(announced[notification.hash], notification)
 
+		case op := <-f.insert:
+			// A direct block insertion was requested, try and fill any pending gaps
+			queued.Push(op, -float32(op.block.NumberU64()))
+			glog.V(logger.Detail).Infof("Peer %s: filled block %x, total %v", op.origin, op.block.Hash().Bytes()[:4], queued.Size())
+
 		case hash := <-done:
 			// A pending import finished, remove all traces of the notification
 			delete(announced, hash)